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Hip Prostheses (hip + prosthesis)
Kinds of Hip Prostheses Selected AbstractsAccelerating aging of zirconia femoral head implants: Change of surface structure and mechanical propertiesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007S. Chowdhury Abstract Recently, alternations of zirconia ceramic femoral heads of total hip prostheses during in vivo conditions have caused concern in the medical disciplines regarding phase transformation of zirconia prosthetic components. In this paper, we have investigated the mechanical and structural properties of different laboratory aged zirconia femoral heads and correlated changes in mechanical properties with the phase compositions of the sample. From laser microscope observation, cross-sectional Scanning electron microscopy imaging, and X-ray diffraction analysis on the surface of the zirconia femoral heads, we found monoclinic to tetragonal phase transformation in zirconia prostheses over time during the aging process in the laboratory. Mechanical properties, mainly hardness (H) and Young's modulus (E) values, were measured by nanoindentation technique on the surface of these implants. The results showed that both H and E values decreased with increased monoclinic phase in zirconia, thus confirming a phase transformation over time during aging. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] New insight into the mechanism of hip prosthesis loosening: Effect of titanium debris size on osteoblast functionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2004Daniel T. O'Connor Abstract The incidence of rheumatoid arthritis and osteoarthritis is on the rise due to our expanding elderly population. Total joint arthroplasty is the most successful, prevalent treatment modality for these and other degenerative hip conditions. Despite the wide array of prosthetic devices commercially available, hip prostheses share a common problem with a gradual and then accelerating loss of bone tissue and bone,implant interface integrity, followed by implant instability and loosening. Implant failure is largely the result of inevitable wear of the device and generation of wear debris. To provide information for the development of improved prosthetic wear characteristics, we examined the effects of size-separated titanium particles on bone forming cell populations. We demonstrate unequivocally that particle size is a critical factor in the function, proliferation, and viability of bone-forming osteoblasts in vitro. In addition, we have elucidated the time-dependent distribution of the phagocytosed particles within the osteoblast, indicating an accumulation of particles in the perinuclear area of the affected cells. The report finds that particle size is a critical factor in changes in the bone formation-related functions of osteoblasts exposed to simulate wear debris, and that 1.5,4 ,m titanium particles have the greatest effect on osteoblast proliferation and viability in vitro. The size of titanium particles generated through wear of a prosthetic device may be an important consideration in the development of superior implant technology. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacementsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2003Christian Lhotka Abstract Background: Metal-on-metal total hip prostheses will produce a certain amount of wear debris. This results in increased whole-blood metal levels, which may cause adverse effects. It is not known to what extent the problem has been overcome by advances in alloy technology. Methods: In 259 patients who with total hip replacement, blood cobalt and chromium concentrations were measured with atomic absorption spectrophotometry over a period of four years after arthroplasty. Of the patients enrolled in the study, 131 had been managed with a METASUL® cobalt-chromium alloy metal-on-metal bearing combination, while 128 had been given a SIKOMET®-SM21® cobalt-chromium alloy metal-on-metal combination. The control group consisted of 31 age- and gender-matched subjects. Results: Compared with the controls, all the patients had higher cobalt and chromium levels. Cobalt concentrations were up to 50 times higher, while chromium concentrations were up to 100 times higher. Conclusions: Both systems showed evidence, in the whole-blood samples, of wear debris production by the implants. Therefore, patients managed with metal-on-metal bearing combinations should be carefully monitored in order to ensure that any local or systemic complications are detected early on. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Wear Simulation of Alumina-on-Alumina Prosthetic Hip Joints Using a Multidirectional Motion Pin-on-Disk DeviceJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2002Vesa Saikko The wear of a state-of-the-art implant alumina against itself was studied with a circularly translating pin-on-disk (CTPOD) device, a wear simulator for prosthetic hip joint materials. The direction of sliding changed continually relative to the pin, preventing erroneous uniaxial grooving typical of ordinary pin-on-disk devices. The dominating wear mechanism was mild abrasion manifested as a relieflike surface, which agreed with clinical findings. The wear factor ranged from 1 × 10,8 to 6 × 10,8 mm3/(N·m). The CTPOD device, validated earlier for ultrahigh molecular weight polyethylene, was shown to be the first simple wear test device to produce wear similar to that known to occur clinically in alumina-on-alumina total hip prostheses. [source] The effects of total hip arthroplasty on the structural and biomechanical properties of adult boneAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Joshua J. Peck Abstract The responsiveness of bone to mechanical stimuli changes throughout life, with adaptive potential generally declining after skeletal maturity is reached. This has led some to question the importance of bone functional adaptation in the determination of the structural and material properties of the adult skeleton. A better understanding of age-specific differences in bone response to mechanical loads is essential to interpretations of long bone adaptation. The purpose of this study is to examine how the altered mechanical loading environment and cortical bone loss associated with total hip arthroplasty affects the structural and biomechanical properties of adult bone at the mid-shaft femur. Femoral cross sections from seven individuals who had undergone unilateral total hip arthroplasty were analyzed, with intact, contralateral femora serving as an approximate internal control. A comparative sample of individuals without hip prostheses was also included in the analysis. Results showed a decrease in cortical area in femora with prostheses, primarily through bone loss at the endosteal envelope; however, an increase in total cross-sectional area and maintenance of the parameters of bone strength, Ix, Iy, and J, were observed. No detectable differences were found between femora of individuals without prostheses. We interpret these findings as an adaptive response to increased strains caused by loading a bone previously diminished in mass due to insertion of femoral prosthesis. These results suggest that bone accrued through periosteal apposition may serve as an important means by which adult bone can functional adapt to changes in mechanical loading despite limitations associated with senescence. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source] High-Turnover Periprosthetic Bone Remodeling and Immature Bone Formation Around Loose Cemented Total Hip JointsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2001Michiaki Takagi Abstract Aseptic loosening and periprosthetic osteolysis are the major problems awaiting solution in total hip surgery. The clinical investigation focused on the analysis of periprosthetic bone remodeling to clarify one important key event in the cascade of periprosthetic connective tissue weakening and osteolysis around loose artificial hip joints. Twelve acetabular bone samples adjacent to granulomatous synovial-like membrane of loose hip prosthesis were retrieved at revision surgery and processed for Villanueva bone staining for morphological observation and bone histomorphometric analysis. Eight well-fixed bony samples were used as control. Although osteoclastic surface and eroded surface by osteoclasts were evident in the periprosthetic bone from loose hip joints (p = 0.003 and p = 0.027), increased osteoid/low-mineralized bone matrix (p < 0.001) and osteoid width (p < 0.001) also were significant findings in structural analysis. In addition, not only elevated mineral apposition rate (MAR; p = 0.044) but also increased mineralizing surface (p = 0.044) and bone formation rate (BFR; p = 0.002) in loose periprosthetic bones were shown in dynamic data analysis. These results were confirmed by precise morphological observation by confocal laser scanning microscopy. Active coupling of bone formation and resorption and increased osteocytes with abundant bone canalicular projections were found in combined with the presence of immature bone matrices (osteoid and low-mineralized bone areas) in periprosthetic bones from loose hip joints. These results indicated that active osteoclastic bone resorption and/or defective bone formation are coupled with monocyte/macrophage-mediated foreign body-type granuloma in the synovial-like interface membrane of loose hip joints. Thus, this unique high-turnover periprosthetic bone remodeling with bad bone quality probably is caused by the result of cellular host response combined with inappropriate cyclic mechanical loading. The fragile periprosthetic bone may contribute to hip prosthesis loosening. [source] Cross-linked N-telopeptide of type I collagen (NTx) in urine as a predictor of periprosthetic osteolysisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006Thord von Schewelov Abstract Periprosthetic osteolysis is often nonsymptomatic and hard to visualize by conventional radiography. Cross-linked N-telopeptide of type I collagen (NTx), a marker of osteoclast mediated bone resorption, has been suggested to evaluate local particulate-induced osteolysis in patients operated on with a total hip prosthesis. Urine specimens were sampled after hip joint replacement in 160 patients. NTx was analyzed by a commercially available ELISA kit. Osteolysis was identified in the acetabulum and confirmed at operation. Using analysis of covariance to correct for differences in age, gender, and time after operation, NTx (mean SD) was 36,±,12 BCE/nM creatinine in patients with osteolysis (n,=,33) and 27,±,13 BCE/nM creatinine in patients without osteolysis (n,=,127) (p,=,0.003). Eighteen hips of 38 (47%), demonstrating an annual wear of more than 0.2 mm and an NTx value above 29 BCE/nM creatinine, had been revised due to osteolysis. The osteolysis prevalence in this group was increased 10 times (CI 4-23, p,<,0.05). Indeed, NTx release and annual wear were both associated with increased prevalence of osteolysis, however, independently of each other. NTx seems a feasible marker of periprosthetic osteolysis. A preoperative baseline NTx level is likely needed for its use as a predictor of periprosthetic osteolysis in individual cases. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1342,1348, 2006 [source] Infection of a total hip prosthesis in a dog caused by Achromobacter(Alcaligenes) xylosoxidansJOURNAL OF SMALL ANIMAL PRACTICE, Issue 12 2006S. L. Girling A four-year-old male, neutered Labrador retriever was presented with progressive left hindlimb lameness 10 months following total hip replacement. Radiography revealed changes consistent with infection and culture of joint fluid from the left coxofemoral joint revealed Achromobacter (Alcaligenes) xylosoxidans. The prosthesis was removed. Culture of the acetabular cup confirmed Achromobacter xylosoxidans. Achromobacter xylosoxidans is an uncommon but serious cause of nosocomial epidemics in hospitals for human beings. To the authors' knowledge, this is the first report of total hip prosthetic infection with Achromobacter xylosoxidans. Little is reported about its pathogenicity in human beings and the authors failed to retrieve any reports of its clinical significance in animals. [source] Finite Element Modelling of Bioactive Contact in Bone-Implant InterfacePROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008André Lutz Finite element simulation for the prediction of bone remodelling caused by implants is a powerful method to improve or to rate implant designs even before they will be evaluated in clinical studies. But the bone,implant interaction is often modelled as ideal bonding in the interface. This approach is not suitable to describe the interrelation of both parts in a physiological manner. To correct these insufficiencies a 3D bioactive contact element has been developed. This contact element describes on the one hand the pure mechanical interaction and on the other hand the mechanical stimulated bone ingrowth in porous surfaces. The benefits of the use of the bioactive contact element regarding the standard method will be presented in this contribution. A comparison of both methods based on clinic results regarding a hip prosthesis with mixed surface textures will be shown. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Is Laterality Associated With a Higher Rate of Hip Arthroplasty on the Dominant Side?ARTIFICIAL ORGANS, Issue 1 2008Susanna Stea Abstract:, The authors analyzed data collected by the Registry of the Orthopedic Prosthetic Implantology in Italy. They found a higher rate of total hip arthroplasty on the right side (58%) in comparison with the left side in patients affected by primary coxarthrosis. To test whether laterality was the cause of this, they checked the prevalence of the upper and lower limbs in 262 patients treated for monolateral total hip prosthesis. They found that the percentage of left-handed patients was very low (0.8,6.5%). The percentage of left-footed patients was, instead, 26.5% for power tasks. They observed that, while the rate of arthroplasties on the right side was similar to that of the left side (50.7 and 49.3%) in the right-footed patients, there was a clear-cut prevalence in the number of operations on the right hip (76.8%) in comparison to the left one (23.2%) in the left-footed patients. The authors suggested that, in left-footed patients, the right side was subjected to greater stress. [source] | ||||||||||||||||